[racket-dev] syntax-local-inferred-name, keyword functions, and syntax properties

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Mon Dec 9 16:50:08 EST 2013

I'm not really familiar with the way the keyword expansion works. I was
just trying to suggest "obvious" reasons why the code would do such a thing.

But if you find that changing the name changes the error message, then
changing that would be bad.

Sorry for the noise.

Robby


On Mon, Dec 9, 2013 at 3:41 PM, Sam Tobin-Hochstadt <samth at cs.indiana.edu>wrote:

> Yes, that would work, but I still don't see why that's a useful name to
> use.
>
> Sam
>
> On Mon, Dec 9, 2013 at 4:37 PM, Robby Findler
> <robby at eecs.northwestern.edu> wrote:
> > Would it work to make it use syntax-local-infer-name but only use the
> > symbolic part of that name?
> >
> > Robby
> >
> >
> >
> > On Mon, Dec 9, 2013 at 3:34 PM, Sam Tobin-Hochstadt <
> samth at cs.indiana.edu>
> > wrote:
> >>
> >> Aha, I found the example:
> >>
> >>    (let ([foo ((lambda (#:kk x) (λ (x) x)) #:k 0)]) (foo 5))
> >>
> >> Has this error:
> >>
> >> application: procedure does not expect an argument with given keyword
> >>   procedure: foo
> >>   given keyword: #:k
> >>   arguments...:
> >>    #:k 0
> >>
> >>
> >> Note that if you make the keywords the same, `foo` is indeed bound to
> >> a procedure, but _not_ to the procedure referred to in the error
> >> message.
> >>
> >> Sam
> >>
> >> On Mon, Dec 9, 2013 at 4:29 PM, Sam Tobin-Hochstadt
> >> <samth at cs.indiana.edu> wrote:
> >> > I haven't found a way to make it happen yet.  But even so, it seems
> >> > like the wrong name.
> >> >
> >> > Sam
> >> >
> >> > On Mon, Dec 9, 2013 at 4:16 PM, Robby Findler
> >> > <robby at eecs.northwestern.edu> wrote:
> >> >> Is it possible that that name can leak out in an error message?
> >> >>
> >> >> Robby
> >> >>
> >> >>
> >> >>
> >> >> On Mon, Dec 9, 2013 at 3:10 PM, Sam Tobin-Hochstadt
> >> >> <samth at cs.indiana.edu>
> >> >> wrote:
> >> >>>
> >> >>> Currently, this program fails with a somewhat bizarre type error:
> >> >>>
> >> >>>     #lang typed/racket
> >> >>>
> >> >>>     (: foo ([#:k Any] -> Integer))
> >> >>>     (define (foo #:k [s #f]) 0)
> >> >>>
> >> >>>     (let: ([i : Integer (foo #:k #t)]) i)
> >> >>>
> >> >>> The reason is that the expansion of keyword applications generates a
> >> >>> name to use for the function (here `foo`), and it uses
> >> >>> `syntax-local-infer-name` to get the name to use. Unfortunately, in
> >> >>> this case, it produces `i`, an identifier which has an extra syntax
> >> >>> property saying that `i` is an `Integer`.  Of course, `foo` isn't an
> >> >>> integer, it's a function, and so we get a type error.
> >> >>>
> >> >>> I don't see why the inferred name is the right choice here --
> there's
> >> >>> no connection between `i` and the name of the function. I can just
> >> >>> change this to use a fresh name, but I thought I'd ask first.
> >> >>>
> >> >>> Sam
> >> >>> _________________________
> >> >>>   Racket Developers list:
> >> >>>   http://lists.racket-lang.org/dev
> >> >>
> >> >>
> >
> >
>
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